1. Field of the Invention
The present invention relates in general to an ink cartridge used for an ink-jet recording apparatus such as an ink-jet printer.
2. Discussion of Related Art
U.S. Pat. No. 6,270,207 corresponding to JP-2000-71472A (FIGS. 1 and 4, in particular) discloses one example of an ink cartridge conventionally used for an ink-jet recording apparatus. The disclosed ink cartridge includes an ink supply hole through which ink is supplied to a printing head of the apparatus and an atmosphere communication hole through which atmosphere is introduced into the inside of the ink cartridge. The ink supply hole and the atmosphere communication hole are sealed by a seal member.
In the disclosed ink cartridge, the ink supply hole and the atmosphere communication hole are first closed by the seal member, and subsequently the pressure of the inside of the ink cartridge is reduced through a pressure reduction hole. In this state, the ink is introduced into the inside of the ink cartridge through an ink filling hole. After the inside of the ink cartridge has been filled with the ink, the pressure reduction hole and the ink filling hole are closed by respective seal members.
In using the conventional ink cartridge constructed as described above, the seal member which closes the ink supply hole and the atmosphere communication hole is first removed or peeled off from the ink cartridge, and then the ink cartridge is installed on the ink-jet recording apparatus. The printing head of the apparatus sucks the ink in the ink cartridge through the ink supply hole, and ejects the ink on a recording medium such as a sheet of paper, so that desired characters and images are recorded on the recording medium. As the ink in the ink cartridge is ejected from the printing head, the atmosphere is introduced into the ink cartridge through the atmosphere communication hole, whereby the ink can be smoothly supplied to the printing head.
For reducing an amount of oxygen dissolved in the ink, the ink cartridge is generally packed in a pressure-reduced state and the inside of the ink cartridge is also kept in a pressure-reduced state. Upon removal of the seal member from the ink cartridge, the atmosphere is sucked into the cartridge through the ink supply hole if the seal member is removed such that the ink supply hole is first exposed to the atmosphere before the atmosphere communication hole is exposed to the atmosphere. In this case, there are generated layers of air and air bubbles in the vicinity of the ink supply hole. If the ink cartridge with the layers of air and air bubbles being present in the vicinity of the ink supply hole is installed on the ink-jet recording apparatus for recording operations, the air is supplied to the printing head, deteriorating the recording quality of the printing head or disabling the printing head from ejecting the ink. To avoid this, in the conventional ink cartridge, there is given an instruction in its manual that the seal member should be removed from the cartridge such that the atmosphere communication hole is first exposed to the atmosphere before the ink supply hole is exposed. Alternatively, as disclosed in JP-10-258519A (FIG. 1, in particular), there are provided, on the seal member, a multiplicity of markings which indicate an appropriate direction of removal of the seal member.